Endoscopy is a well-known procedure for examining the internal organs. The procedure is performed under the guidance of an endoscope. Currently used fiber optic endoscopes include lenses mounted in a flexible tube that relay an image from inside a body cavity for viewing by a physician for diagnosis or manipulation inside the body cavity.
In performing an endoscopy, it is common to insufflate (introduce air into) the gastrointestinal tract in order to provide easier visualization. This can cause bloating and discomfort to the patient or, in rare cases, severe abdominal pain.
More recently, echoendoscopy has been introduced. An echoendoscope (EUS) is a device that combines endoscopy and ultrasound to image the gastrointestinal wall and surrounding structures.
The ultrasound transducer is positioned at the distal tip of endoscope; the key components of the transducer are the piezoelectric crystals that vibrate to produce ultrasonic waves. The ultrasonic waves travel through the gastrointestinal wall and beyond the visceral wall into the surrounding organs. The reflection of these ultrasound waves is detected by the same crystals at the transducer and reconstruction of these reflections will result in creating a real time image of the gastrointestinal wall and its surrounding structures. The ultrasonic wave reflects from the surface of structures with different density and can pass very well through fluid containing and solid structures. Air, however, creates a barrier to ultrasonic wave passage and hampers the obtaining of ultrasonic images.
Several attempts have been made to minimize the amount of interfering air between the transducer and the examining structure. The prior art teaches the use of balloons at the end of the endoscope that encloses the transducer and is filled with water to permit acoustic coupling between the transducer and the luminal wall or other gastrointestinal structures. This is particularly helpful in the part of the gastrointestinal tract where the diameter of the lumen is small and the inflated balloon makes good circumferential contact with the intestinal wall and thus creates a good acoustic coupling. In most parts of the gastrointestinal tract, however, the large diameter of the lumen and/or the angle of the transducer in relation to the intestinal wall results in an inadequate contact between the transducer balloon and the intestinal wall. Therefore, operators usually use water infusion to fill the region of the gastrointestinal tract with water and create acoustic coupling between the transducer and the examined structures.
A significant shortcoming of this prior art is that it does not account for the fact that the gastrointestinal tract is not a closed region and the infused water soon moves to other regions of the gastrointestinal tract. Infusion of significant amounts of water during the examination could result in untoward problems such as aspiration of the water into the patient's airway or over distention of the gastrointestinal tract.
Further advances in the prior art include two-balloon approaches for assisting the movement of the endoscope. However, these prior art devices utilize the balloons only to secure and maintain positioning of the endoscope or to seal two separate anatomical structures from one another. To advance the endoscope, the balloons must be deflated and inflated in alternating order. Yet further attempts have taught the use of an overtube that consists of a device having a window near its distal end through which the endoscopic examination can be performed. A shortcoming of this approach is that it limits the maneuverability of the endoscope and may create noise, thereby diminishing the accuracy of a procedure.
There is need, therefore, for an examination accessory for endoscopic examination that creates an examination partition around the endoscope tip. Such a device will create an examination compartment proximal and distal to the endoscope or ultrasound tip. The examination compartment can then be filled with air, water or could be thoroughly lavaged using the device. Such a device may further include balloons comprising at least a positioning ring for maintaining the position of the endoscope accessory in an area to be examined and to seal the proximal end of the examination partition independent of the endoscope tip and may also include an independently positionable occlusion balloon distal to the tip of the endoscope or echoendoscope for sealing the distal end of the examination partition. There is further need for such a device that can be advanced or retracted without the necessity of deflating and re-inflating the balloons, thereby creating a movable examination compartment. There is further need for such a device that can be placed on an endoscope shaft without the necessity of having to remove the endoscope from the body. Some embodiments of the present invention provide such a device.